Method of Deactivating High-Speed Downlink Operation in Cell_fach State for a Wireless Communications System and Related Apparatus

1. A method for improving a determining procedure of stopping a high speed downlink operation corresponding to a CELL_FACH state for a user equipment, also called UE, in the CELL_FACH state in a wireless communications system, the method comprising: changing a setting of a dedicated variable corresponding to a dedicated HS-DSCH radio network transaction identifier, hereinafter called H-RNTI, from a use state to a close state; and determining that the setting of the dedicated variable and a setting of a common variable corresponding to a common H-RNTI are valid configuration if both the setting of the dedicated variable is a close state and the setting of the common variable is a close state, wherein determining that the setting of the dedicated variable and the setting of the common variable are valid configuration if both the setting of the dedicated variable is a close state and the setting of the common variable is the close state is determining that a setting of an HS DSCH RECEPTION CELL FACH STATE variable and a setting of an HS DSCH RECEPTION OF CCCH variable are valid configuration if both a setting of the HS DSCH RECEPTION CELL FACH STATE variable is “FALSE” and a setting of the HS DSCH RECEPTION OF CCCH variable is “FALSE” and wherein determining that the setting of the dedicated variable and the setting of the common variable are the valid configuration comprises maintaining a setting of an INVALID CONFIGURATION variable “FALSE”.

2. The method of claim 1 further comprising stopping the high speed downlink operation when the setting of the dedicated variable changes from the use state to the close state and the setting of the common variable is the close state.

3. The method of claim 1 , wherein the high speed downlink operation comprises reception of a high speed downlink shared channel, abbreviated to HS-DSCH.

4. The method of claim 1 , wherein changing the setting of the dedicated variable from the use state to the close state is changing a setting of an HS_DSCH_RECEPTION_CELL_FACH_STATE variable from “TRUE” to “FALSE”.

5. A communications device in a CELL_FACH state of a wireless communications system for improving a determining procedure of stopping a high speed downlink operation corresponding to the CELL_FACH state to avoid degrading the packet transmission performance, the communications device comprising: a control circuit for realizing functions of the communications device; a central processing unit coupled to the control circuit for executing a program code to operate the control circuit; and a memory coupled to the central processing unit for storing the program code; wherein the program code comprises: changing a setting of a dedicated variable corresponding to a dedicated HS-DSCH radio network transaction identifier, hereinafter called H-RNTI, from a use state to a close state; and determining that the setting of the dedicated variable and a setting of a common variable corresponding to a common H-RNTI are valid configuration if both the setting of the dedicated variable is a close state and the setting of the common variable is a close state, wherein determining that the setting of the dedicated variable and the setting of the common variable are valid configuration if both the setting of the dedicated variable is a close state and the setting of the common variable is the close state is determining that a setting of an HS DSCH RECEPTION CELL FACH STATE variable and a setting of an HS DSCH RECEPTION OF CCCH variable are valid configuration if both a setting of the HS DSCH RECEPTION CELL FACH STATE variable is “FALSE” and a setting of the HS DSCH RECEPTION OF CCCH variable is “FALSE” and wherein determining that the setting of the dedicated variable and the setting of the common variable are the valid configuration comprises maintaining a setting of an INVALID CONFIGURATION variable “FALSE”.

6. The communications device of claim 5 , wherein the program code further comprises stopping the high speed downlink operation when the setting of the dedicated variable changes from the use state to the close state and the setting of the common variable is the close state.

7. The communications device of claim 5 , wherein the high speed downlink operation comprises reception of a high speed downlink shared channel, abbreviated to HS-DSCH.

8. The communications device of claim 5 , wherein changing the setting of the dedicated variable from the use state to the close state is changing a setting of an HS_DSCH_RECEPTION —CELL _FACH_STATE variable from “TRUE” to “FALSE”.